KR20230005341A - Pixel structures for electronic displays and electronic devices incorporating such displays - Google Patents

Abstract

A pixel structure (1) for an electronic display (2) comprising a substrate (3), at least one LED emitter (4) arranged on the substrate (3) and an LED on the substrate (3). and at least one wavelength conversion unit (5) arranged adjacent to the emitter (4). The LED emitter 4 is configured to emit emission radiation R1, which emission radiation R1 is within a range of emission wavelengths and is emitted in one or several emission directions D2,...,Dn within a main emission plane P1. do. The wavelength conversion unit 5 is configured to convert the emission radiation R1 into converted radiation R2 within a converted wavelength range, the converted wavelength range being different from the emission wavelength range. The converted radiation R2 propagates from the wavelength conversion unit in a main conversion direction D1 perpendicular to the main emission plane P1, the main conversion direction D1 comprising, for example, at least one such pixel structure. A direction toward the user of an electronic device having a display. Each pixel structure has six LED emitters (4), a first pair of LED emitters (4) operably connected to the first wavelength conversion unit (5), operably connected to the second wavelength conversion unit (5). a second pair of LED emitters (4), and a third pair of LED emitters (5), each of which emits direct emission radiation in a main conversion direction (D1) or a radiation scattering unit (6). ) or further wavelength conversion units 5 respectively.

Description

Pixel structures for electronic displays and electronic devices incorporating such displays

The present disclosure relates to a pixel structure for an electronic display, which pixel structure includes at least one LED emitter and at least one wavelength conversion unit arranged on a substrate. The present disclosure also relates to an electronic device comprising an electronic display having a user interface surface and at least one such pixel structure.

Micro-light emitting diodes, also known as Micro-LEDs, mLEDs or uLEDs, are used in displays for mobile devices such as smartphones, TVs, PCs, tablets, smart glasses, wearables and many other consumer and industrial devices. Micro LEDs, usually composed of multiple arrays of small LED emitters, are a promising future display technology with many potential advantages, such as high brightness and contrast, high power efficiency, wide color gamut and form factor flexibility, and integration of various functions.

Micro LED display technology mainly uses one of two methods: direct emission or color conversion.

In direct emission mode, each individual LED emitter emits radiation in the red, green or blue spectral range. This direct emission solution is very expensive to manufacture because each pixel structure requires one red spectral range emitter, one green spectral range emitter and one blue spectral range emitter, so the resolution is about 8 million pixels. This is because a phosphor-in display requires about 24 million LED emitters.

In the color conversion scheme, only LED emitters are used that emit radiation in the blue spectral range, for example. LED emitter chips are usually based on the GaN (gallium nitride) material system. Blue-red and blue-green emission conversion units are stacked over corresponding LED pixels and are used to convert blue spectral range radiation from some LED emitters to red spectral range radiation or green spectral range radiation, respectively. Compared to direct emission, color conversion is easier and cheaper to manufacture because only one type of LED emitter is required.

Radiation in the blue spectral range is partially absorbed by the conversion unit, and this absorption decreases exponentially in the first order. Ideally, almost all of the blue spectral range radiation should be absorbed by the conversion unit to keep energy efficiency high and to minimize blue spectral range radiation leakage from the conversion unit.

Also, the conversion unit should have similar area dimensions to the LED emitter. The height of the conversion unit is preferably larger to form a small pole over the small size LED emitter. This facilitates absorption by enabling a greater distance for blue spectral range radiation to propagate through the conversion unit.

However, in practice, to absorb most of the radiation in the blue spectral range, the conversion material must be one or several hundred micrometers thick. This provides a very large aspect ratio of more than 100 μm : 3 μm between the LED emitter and the conversion unit, which is not easy to achieve using microstructuring methods. Another problem is that either green spectral range radiation or red spectral range radiation must propagate through the conversion unit and may be slightly absorbed (self-absorbed) by the material of the conversion unit. This reduces the effectiveness of the device.

Also, this stacked structure has poor heat dissipation since the heat from the conversion unit has to pass through the LED emitter chip underneath. This further heats the LED emitter chip and shortens the lifetime of the pixel structure. Lamination also makes it difficult to integrate other functional optical elements, such as lenses.

It is an object to provide an improved micro LED pixel structure. The foregoing and other objects are achieved by the features of the independent claim(s). Further implementation forms are apparent from the dependent claims, detailed description and drawings.

According to a first aspect, there is provided a pixel structure for an electronic display comprising a substrate and at least one LED emitter arranged on the substrate, the LED emitter being configured to emit emission radiation, comprising: radiation in a range of emission wavelengths and emitted in one or more emission directions within a main emission plane; and at least one wavelength conversion unit disposed on the substrate adjacent to the LED emitter, the wavelength conversion unit converting the emission radiation into converted radiation, wherein the converted radiation is within a converted wavelength range and propagates from the wavelength conversion unit in a main converted direction perpendicular to a main emission plane, the converted wavelength range being different from the emission wavelength range.

This arrangement enables a pixel structure with a significantly reduced height since the conversion unit is arranged adjacent to the LED emitter as opposed to being stacked on top of the LED emitter. This type of distribution improves the heat dissipation of the structure and consequently improves the lifetime of the pixel structure. Also, since the converted radiation extends substantially perpendicular to the emitted radiation, the emitted radiation leaks in the direction of the converted radiation, for example in the blue spectral range, to the converted radiation in the red spectral range or the green spectral range, for example. The risk of being affected is greatly reduced. Higher efficiencies are also achieved due to direct propagation of the converted radiation from the conversion unit, without interaction and re-absorption of the converted radiation by other conversion units.

In a possible implementation of the first aspect, the main emission plane is parallel to the main substrate plane of the substrate, and the LED emitter(s) and wavelength conversion unit(s) are distributed in the main emission plane.

In a further possible implementation of the first aspect, the emission wavelength range is either the blue spectral range or the ultraviolet spectral range, and when the pixel structure includes at least two LED emitters, the LED emitters are configured to emit radiation having the same wavelength. do. If only one type of LED emitter is used, manufacturing of the pixel structure is much simpler and cheaper, since only one main component is required, instead of, for example, three different but equally important main components. .

In a further possible implementation form of the first aspect, the pixel structure includes at least two wavelength conversion units, each wavelength conversion unit converting emitted radiation within an emission wavelength range to converted radiation within one of a plurality of different converted wavelengths. configured to facilitate converting emitted radiation of the same wavelength into converted radiation within any of several different wavelength ranges.

In a further possible implementation form of the first aspect, the at least one first wavelength conversion unit is configured to convert the emitting radiation into a first converted radiation within the first converted wavelength range, and the at least one second wavelength conversion unit is configured to convert the emitted radiation to and convert the radiation to second converted radiation within a second converted wavelength range, wherein the second converted wavelength range differs at least in part from the first converted wavelength range. This allows one pixel structure radiation to emit radiation in several different wavelength ranges simultaneously and in the same direction.

In a further possible implementation of the first aspect, the first converted wavelength range is within the red spectral range and the second converted wavelength range is within the green spectral range, facilitating creation of a commonly used RGB pixel structure.

In a further possible implementation form of the first aspect, the LED emitter is configured to emit emission radiation only in a main emission plane, or the emission radiation emitted in the main emission plane by the LED emitter or at least one portion of the emission radiation is transmitted from the wavelength conversion unit. converted into converted radiation. This allows the pixel structure to have a height as low as possible, i.e. the height seen in the main transform direction, increasing the freedom to place the LED emitter at any suitable location within the electronic device while freeing up space for other components. allows you to secure

In a further possible implementation form of the first aspect, when the pixel structure includes at least two LED emitters, at least one of the LED emitters is configured to emit emission radiation in a main conversion direction, for example emission radiation in the blue spectral range. can be emitted directly into the user interface without conversion or redirection.

In a further possible implementation form of the first aspect, the pixel structure further comprises at least one radiation scattering unit arranged adjacent to the LED emitter on the substrate, the scattering unit generating emission radiation propagating in the main emission plane. to the main conversion unit, allowing a portion of the emitted radiation to change direction, providing more freedom with respect to placement of the LED emitter within the electronic device.

In a further possible implementation form of the first aspect, the wavelength conversion unit includes a wavelength conversion material, and the wavelength conversion material preferably includes a matrix material and wavelength conversion particles distributed in the matrix material.

In a further possible implementation of the first aspect, the wavelength converting particles are quantum dots or phosphorous materials.

In a further possible implementation form of the first aspect, the wavelength conversion unit includes at least one barrier extending along the periphery of the wavelength conversion unit in a main conversion direction, the barrier extending an absorption path of the wavelength conversion unit. wherein the absorption path extends from the main emission plane, the emission radiation propagates along the absorption path, and conversion of the emission radiation into converted radiation occurs concurrently with the propagation. Through a barrier, individual pixel structures can be distributed at a smaller pitch, since the barrier helps to reduce or even avoid optical cross talk between adjacent pixel structures, even if they are close together. Additionally, the barrier can serve as a supporting surface for reflectors used to redirect radiation.

In a further possible implementation form of the first aspect, the pixel structure further comprises at least one wall reflector arranged on a surface of the barrier extending at least partially in the main transformation direction, the wall reflector generating emission radiation propagating along the absorption path. , so that the absorption path of the wavelength conversion unit extends within the main emission plane, so that as much emission radiation as possible is absorbed and thus converted by the wavelength conversion unit.

In a further possible implementation form of the first aspect, the pixel structure includes at least one bottom reflector arranged between the wavelength conversion unit and the substrate, the bottom reflector extending at least partially parallel to the main emission plane and propagating within the wavelength conversion unit. configured to redirect the converted radiation into the main converted direction, facilitating enhancement of the output radiation efficiency.

In a further possible implementation of the first aspect, at least one of the wall reflector and the floor reflector extends at an angle to the main transform direction, such that emitted radiation and/or converted radiation is redirected towards a more useful direction when striking the reflector. make it possible

In a further possible implementation form of the first aspect, the wavelength conversion unit comprises a waveguide structure configured to guide the emission radiation as it propagates within the wavelength conversion unit, so that the wavelength conversion unit is configured to form factors of the electronic device and peripheral components to be able to adapt to

In a further possible implementation form of the first aspect, the wavelength conversion unit is configured such that the at least one wavelength conversion unit surface extends at an angle with respect to a main substrate plane of the substrate, the surface facing away from the substrate and the surface adjacent to the substrate. is extended by This solution helps prevent total internal reflection from occurring because the angle can be adjusted to allow as much converted radiation as possible to propagate out of the wavelength converter in the main conversion direction.

In a further possible implementation of the first aspect, one of the wavelength conversion unit and the substrate is tapered as it extends along the main emission plane or main substrate plane, such that the wavelength conversion unit surface is not angled by the simplest possible means. allow that

In a further possible implementation form of the first aspect, the pixel further comprises at least one optical function element arranged on a surface of the wavelength conversion unit facing away from the substrate, the optical function element arranged on top of the surface of the wavelength conversion unit or on the surface of the wavelength conversion unit. integrated with the surface.

In a further possible implementation form of the first aspect, the optical functional element is at least one of a refractive lens and a diffractive lens, for example to enhance focus of the converted radiation.

In a further possible implementation form of the first aspect, the optical functional element is a surface structure, preferably one of a surface lattice structure, a surface roughness structure, a surface coating structure or a micro-column, to improve the separation efficiency of the pixel structure.

In a further possible implementation form of the first aspect, several of the plurality of LED emitters are operably connected to one wavelength conversion unit, the LED emitters being configured to simultaneously and independently emit emitting radiation to the wavelength conversion unit. Not only does this provide redundancy which provides better yield, but even if one of the LED emitters fails, the pixel structure still continues to operate as intended without dark areas.

In a further possible implementation form of the first aspect, the pixel structure includes six LED emitters, wherein the first pair of LED emitters are operatively connected to a first wavelength conversion unit, the first wavelength conversion unit comprising: configured to convert emitted radiation from the LED emitters to first converted radiation, the second pair of LED emitters being operably connected to a second wavelength conversion unit, the second wavelength conversion unit from the second pair of LED emitters. wherein each LED emitter of the third pair of LED emitters is operably connected to one radiation scattering unit or one further wavelength conversion unit; This additional wavelength conversion unit is configured to convert the emitted radiation from the third pair of LED emitters into third converted radiation. This provides a pixel structure capable of redundantly and simultaneously emitting radiation at three wavelengths.

In a further possible implementation form of the first aspect, the pixel structure further comprises a control device for adjusting the total output of the converted radiation, the adjusting comprising one of pulse width modulation and adjustment of the drive current of the LED emitter(s). include The control device can for example use built-in redundancy as appropriate, e.g. allow pairs of LED emitters to be manipulated so that they provide a better yield or one LED emitter compensates for a failed other LED emitter of the LED emitter pair. do.

According to a second aspect, an electronic device comprising an electronic display having a user interface surface and at least one pixel structure according to the above is provided. The pixel structure is such that emission radiation of one emission wavelength is emitted in multiple emission directions within a main emission plane, the main emission plane extending parallel to the user interface surface, to direct at least a portion of the emission radiation into at least one converted wavelength-converted The wavelength is different from the emission wavelength and is configured to direct the converted radiation in a main converted direction perpendicular to the main emission plane and the user interface surface.

This pixel structure has a greatly reduced height, thus leaving room for other components inside the electronic device or providing additional freedom to the form factor of the device. Electronic displays will also have improved lifetime due to improved heat dissipation of the pixel structure. Also, since the fill factor of the pixel structure in the lateral direction, i.e. the direction within the main emitting plane, is low in many electronic devices, this structure leaves a lot of free space to accommodate the conversion unit while still adding additional components or structures. It provides ample degrees of freedom for improvement.

In a possible implementation of the second aspect, the electronic device includes a plurality of identical pixel structures, the pixel structures are distributed in a main emission plane in a two-dimensional pattern, the two-dimensional pattern comprising rows of pixel structures and columns of pixel structures. where the rows extend parallel and intersect the columns at a vertical angle, the number of pixel structures in an individual row is independent of the number of pixel structures in adjacent rows, and the number of pixel structures in an individual column is independent of the number of pixel structures in adjacent columns. Independent, the distribution of pixel structures allows maximization of the number of pixel structures in the region containing the two-dimensional pattern, if desired, and simpler structures when maximization is not required.

In a further possible implementation form of the second aspect, the plurality of pixel structures is such that at least a first emission direction of the emission radiation of an individual pixel structure is sufficient for a far-view display, for example a corresponding first pixel structure of an adjacent pixel structure. 1 are distributed in a first pitch according to a two-dimensional pattern so as to be aligned with the emission direction.

In a further possible implementation form of the second aspect, the plurality of pixel structures is such that at least a first emission direction of the emission radiation of an individual pixel structure corresponds to a corresponding first direction of an adjacent pixel structure required, for example, for a near-view display. Distributed in a second pitch according to the two-dimensional pattern, not aligned with one emission direction, allowing maximization of the number of pixel structures in the region containing the two-dimensional pattern.

In a further possible implementation form of the second aspect, the pixel structures are separated by a first pitch, and the pixel structures are aligned in at least one of a column direction and a row direction, so that the absorption path(s) of the wavelength conversion unit(s) of the individual pixel structures is aligned with the corresponding absorption path(s) of adjacent pixel structures.

In a further possible implementation form of the second aspect, the pixel structures are separated by a second pitch, and each pixel structure is rotated by a predetermined angle from the main emission plane, so that the absorption path of the wavelength conversion unit(s) of the individual pixel structure ( s) are misaligned with the corresponding absorption path(s) of adjacent pixel structures, where the misalignment is the lateral offset and/or angular offset in the direction of each pixel structure.

In a further possible implementation form of the second aspect, the pixel structures in an individual row are offset in a column direction with respect to the pixel structures in adjacent rows, and/or the pixel structures in an individual column are offset in a row direction with respect to the pixel structures in adjacent columns.

In a further possible implementation form of the second aspect, the length of the absorption path is fixed, and in display applications configured such that the distance between the user's eye and the user interface surface 2a is <1 m, the length is 10-500 μm, preferably <20 μm and the second pitch is 20-150 μm, preferably 30-80 μm, and in display applications configured such that the distance between the user's eyes and the user interface surface 2a is ≥ 0.5 m, the second pitch is ≥ 0.5 m. 70 μm, preferably ≧100 μm.

In an additional possible implementation form of the second aspect, the transformed radiation is propagated in the main transformation direction toward the user interface surface without application of radiative filtering, reducing the number of components required, the space required for the pixel structure, and the number of error sources. .

These and other aspects will be apparent from the examples described below.

In the following detailed portion of the present disclosure, aspects, embodiments and implementations will be described in more detail with reference to exemplary embodiments shown in the drawings.
1A and 1B show side and top views of a prior art pixel structure.
2A and 2B show side and top views of a pixel structure according to an embodiment of the present invention.
3A and 3B show top and side views of a pixel structure according to an embodiment of the present invention.
4 to 9 show partial cross-sectional views of pixel structures according to different embodiments of the present invention.
10 shows a schematic side view of an electronic device including a pixel structure according to an embodiment of the present invention.
11 to 18 show schematic top views of the distribution of pixel structures for electronic displays.

1A and 1B show side and top views of a color conversion pixel structure according to the prior art. Some LED emitters 4 emit emission radiation R1 in direction D1, for example within the blue spectral range. The conversion unit 5 stacked on top of the LED emitter 4 absorbs the emitted radiation R1, converts it into converted radiation R2, and then converts the converted radiation R2 also in the direction D1. emit with

2A and 2B show side and top views of one embodiment of a color conversion pixel structure in accordance with the present invention. 3A to 9 show a further embodiment of a color conversion pixel structure. This color conversion pixel structure is used in the electronic display 2, and the display includes a required number of identical pixel structures.

The pixel structure 1 comprises a substrate 3 configured to support at least one LED emitter 4 and at least one wavelength arranged adjacent to the LED emitter 4 on the substrate 3, as shown in FIG. 2A. Conversion unit 5 is included. The LED emitter 4 , the wavelength conversion unit 5 and further components mentioned further below can be connected to the substrate 3 by soldering, adhesives or nanowires. The substrate 3 may comprise one integral substrate or several aligned partial substrates, and extends at least partially within one main substrate plane P2. While the substrate 3 may have a partially stepped configuration, each pixel structure 1 is arranged in one common plane such that both its radiation emission and radiation conversion components are aligned with the main emission plane P1. The main radiation plane P1 extends parallel to the main substrate plane P2 of the substrate 3 as shown in FIG. this is distributed With this distribution, the wavelength conversion unit 5 has a height of the order of 10 to 100 μm in the main conversion direction D1, while the length/width of the wavelength conversion unit 5 may exceed 100 μm, even exceed 1000 μm. can

One or several LED emitter(s) is arranged on a substrate 3 such that each LED emitter 4 can emit emission radiation R1 within a main emission plane P1, ie laterally through the side of the LED emitter. ) are arranged on The emission radiation R1 emitted by the LED emitter 4 is emitted only in a first emission direction D2, or a plurality of emission directions D2 covering part or all of a 360° area around the LED emitter 4. ,..., Dn). Emitted radiation R1 is also referred to as pump light.

All emission radiation R1 emitted by the plurality of LED emitters 4 are within one and the same emission wavelength range. The emission wavelength range may be in the blue spectral range or in the ultraviolet spectral range.

Each wavelength conversion unit 5 is configured to convert the emitted radiation R1 into converted radiation R2. The converted radiation R2 is within a converted wavelength range that is at least partially, preferably completely different from the emission wavelength range. Different wavelength conversion units 5 can convert the emitted radiation R1 into converted radiation R2 within different converted radiation ranges R21 and R22. The pixel structure 1 may comprise a plurality of wavelength conversion units 5, each wavelength conversion unit 5 converting the emitted radiation R1 within one of the plurality of converted wavelength ranges to the converted radiation R2 ) is configured to convert to

In an embodiment, the pixel structure 1 has at least one first wavelength configured to convert the emitted radiation R1 into a first converted radiation R21 within a first converted wavelength range, for example a red spectral range. Conversion unit 5 and at least one second wavelength conversion unit 5 configured to convert the emitted radiation R1 into a second converted radiation R22 within a second converted wavelength range, for example within the green spectral range. ).

In a further embodiment, the pixel structure 1 converts the emitted radiation R1 into converted radiation in the red spectral range R21 into converted radiation in the green spectral range R22 and into the converted radiation in the yellow spectral range R23 ( and a wavelength conversion unit 5 for converting into converted radiation in (not shown). The pixel structure 1 comprises any number of wavelength conversion units 5 which convert the emitted radiation R1 into any number of radiation within the desired spectral range R2, R21, R22, R23,...,R2n. can include

The converted radiation R2 propagates from the wavelength conversion unit 5 in a main conversion direction D1 extending substantially perpendicular to the main emission plane P1, ie through the upper surface of the wavelength conversion unit 5. . That is, the converted radiation R2 propagates in a direction away from the substrate 3 towards, for example, the user interface surface 2a of the electronic device 13 included in the electronic display 2 .

In one embodiment shown in FIG. 4 , at least one of the LED emitters 4 is configured to emit emission radiation R1 directly in the main conversion direction D1, ie the emitted emission radiation R1 is directed in the main conversion direction D1. When propagating in (D1), it maintains its own direction and wavelength.

In a further embodiment shown in FIGS. 5 to 7 , the LED emitter(s) 4 is provided only in the main emission plane P1 , ie not directly in the main transforming direction D1 , but at least one of the LED emitter(s) 4 It is configured to emit emission radiation R1 to the wavelength conversion unit 5 or the plurality of conversion units 5 in a lateral direction through a side or all sides of the . The wavelength conversion unit 5 may be arranged to convert the emitted radiation R1 emitted from one or all sides of the LED emitter 4 or only a part of the emitted radiation R1 into converted radiation R2.

In a further embodiment, the pixel structure 1 comprises at least one radiation scattering unit 6 as shown in FIG. 5 . The radiation scattering unit 6 is arranged on the substrate 3 adjacent to the LED emitter 4 similarly to the arrangement of the wavelength conversion unit 5 . The scattering unit 6 is configured to redirect the emission radiation R1 propagating in the main emission plane P1 into the main conversion direction D1 without conversion, ie without changing the wavelength of the emission radiation R1. The scattering unit 6 may comprise a polymeric matrix material such as polymethyl methacrylate (PMMA) with scattering particles dispersed within the matrix material. The scattering particles scatter the incoming emission radiation R1 in all directions, preferably the radiation R1 directed towards the bottom of the scattering unit 6, i.e. the substrate 3, for example a bottom reflector ( 9) is easily redirected towards the top of the scattering unit 6 through a reflector. The scattering unit 6 may have a height in the main transform direction D1 of the order of 10 to 100 μm, while the length/width of the scattering unit 6 may be greater than 100 μm, even greater than 1000 μm. Generally, the amount of scattering particles is large enough so that the scattering unit 6 has a relatively low height.

Each wavelength conversion unit 5 contains a wavelength conversion material. The wavelength converting material may be a matrix material comprising wavelength converting particles distributed within the matrix material. Wavelength converting particles may be quantum dots or phosphorous materials.

As shown in FIG. 6 , the wavelength conversion unit 5 may include at least one barrier 7 extending along the periphery of the wavelength conversion unit 5 in the main conversion direction D1 . The barrier 7 is along at least one long edge (not shown) of the wavelength conversion unit 5, along one short end of the wavelength conversion unit 5 as shown in FIG. 6, or along the wavelength conversion unit ( 5), so that the wall of the wavelength conversion unit 5 is covered by the barrier 7 at least in the main conversion direction D1 as shown in FIGS. 11 and 15 . The barrier 7 may be integrated between adjacent pixel structures 1 by nanoimprinting technology with a polymer layer or photolithography of a photosensitive polymer material such as BCB (benzocyclobutene).

The barrier 7 is configured to extend the absorption path A of the wavelength conversion unit 5 . The absorption path A extends in the main emission plane P1 within the wavelength conversion unit 5 . As the emission radiation R1 propagates in the wavelength conversion unit 5, this emission radiation R1 is also absorbed along the absorption path A. As shown in Figures 4-9, the absorption and thus conversion of the emitted radiation R1 to converted radiation R2 occurs simultaneously with the propagation. As the emitted radiation R1 propagates along the absorption path A, the intensity of the emitted radiation R1 generally decreases exponentially.

The barrier 7 reduces optical crosstalk occurring between adjacent pixel structures 1 and allows the absorption path A of the wavelength conversion unit 5 to be extended by the at least one wall reflector 8 .

In one embodiment shown in FIG. 6, at least one wall reflector 8 is arranged on the barrier 7, preferably on a surface of the barrier 7 extending at least partially in the main turning direction D1. do. The wall reflector 8 is configured to redirect the emission radiation R1 propagating along the absorption path A such that the absorption path A of the wavelength conversion unit 5 extends within the main emission plane P1. . This folding of the absorption path (A), which can be up to 180° from the original emission direction (D2,...,Dn) is shown in FIG. 11 .

4 to 9, between the wavelength conversion unit 5 and the substrate 3, preferably on the upper surface of the substrate 3 on which the LED emitter 4 and the wavelength conversion unit 5 are distributed. At least one bottom reflector 9 can be arranged. The bottom reflector 9 extends at least partially parallel to the main emission plane P1 and transmits converted radiation R2 propagating within the wavelength conversion unit 4 in substantially all directions towards the main conversion direction D1. It is configured to redirect. For example, the converted radiation R2 directed towards the bottom of the wavelength conversion unit 5 , ie the substrate 3 , is easily redirected towards the top of the wavelength conversion unit 5 .

The wall reflector 8 and/or the bottom reflector 9 may extend at an angle to the main transforming direction D1. The wall reflector 8 has a main emission plane P1 such that the emitted radiation R1 impinging on the wall reflector 8 is directed towards the substrate 3, preferably towards the bottom reflector 9 or towards the user interface surface 2. ) may extend at an angle that is not perpendicular to The bottom reflector 9 may extend parallel to the main emission plane P1, or may extend at an angle to the main emission plane P1, to reflect the emission radiation R1 propagating towards the substrate 3. Thus, the reflection of the emitted radiation R1 propagating towards the substrate 3 can be steered in a specific predetermined direction. The wall reflector 8 and/or the bottom reflector 9 may comprise a reflective surface, preferably a metal layer. The metal layer may be a sputtered aluminum layer, in which case the wall reflector 8 and/or bottom reflector 9 also prevents optical crosstalk between adjacent pixel structures.

Correspondingly, the wavelength conversion unit 5 may be configured such that the at least one wavelength conversion unit surface 5a, 5b extends at an angle α relative to the main substrate plane P2 of the substrate 3, and the surface ( 5a) faces away from the substrate 3 and the surface 5b extends adjacent to the substrate 3 . At least one of the wavelength conversion unit surfaces 5a, 5b is formed because the wavelength conversion unit 5, the substrate 3 or both are wedge-shaped, i.e. along the main emitting surface P1 or the main substrate surface P2. As it is tapered as it extends, it extends at an angle α. FIG. 7 shows an embodiment in which only the wavelength conversion unit surface 5a extends at an angle α with respect to the main substrate plane P2 of the substrate 3 because the wavelength conversion unit 5 itself is tapered. Both the wavelength conversion unit surfaces 5a and 5b may extend at an angle α with respect to the main substrate plane P2 of the substrate 3 . Further, the wavelength conversion unit surface 5a may extend at an angle α1, and the wavelength conversion unit surface 5b may extend at an angle α2. Due to the high refractive index of the wavelength conversion unit matrix material, only the converted radiation R2 impinging on the wavelength conversion unit surfaces 5a, 5b at an angle smaller than the critical angle for total internal reflection, compared to the surrounding air, causes the wavelength conversion unit 5 to , the other converted radiation R2 is reflected off the wavelength conversion unit surfaces 5a, 5b and remains inside the wavelength conversion unit 5. By applying the aforementioned tapering wedge shape, the radiant output efficiency is enhanced, because as the radiation captured in the wavelength conversion unit 5 is reflected, this radiation eventually travels at a smaller angle to the wavelength conversion unit surfaces 5a, 5b. ) will collide with

As shown in FIG. 12 , wavelength conversion unit 5 may include a waveguide structure 10 configured to guide emitted radiation R1 as it propagates within wavelength conversion unit 5 . The waveguide structure may have any suitable shape, for example curved or spiral (not shown) as in FIG. 12 .

The pixel structure 1 may further include at least one optical functional element 11 arranged on the wavelength conversion unit surface 5a facing away from the substrate 3 as shown in FIGS. 8 and 9 . The optical functional element 11 may be arranged on top of the wavelength conversion unit surface 5a as shown in FIG. 9 or integrated with the wavelength conversion unit surface 5a as shown in FIG. 8 .

The optical functional element 11 shown in FIG. 9 may be, for example, at least one of a refractive lens and a diffractive lens used to focus the converted radiation R2.

Instead, the optical functional element 11 may have a surface structure, preferably one of a surface lattice structure, a surface roughness structure, a surface coating structure, or micro-pillars as shown in FIG. 8 . The surface grating structure improves the outcoupling efficiency of the converted radiation R2 by steering the converted radiation R2.

As shown in FIG. 2B, several LED emitters 4 can be operably connected to one wavelength conversion unit 5, and emit emission radiation R1 to the wavelength conversion unit 5 simultaneously and independently. can be configured to This not only provides redundancy enabling better yields, but also ensures that if one of the LED emitters 4 fails, the pixel structure 1 will still function as intended without any dark areas.

As shown in FIG. 10 , a control device 12 is provided for adjusting the total output of the converted radiation R2 , R21 , R22 , the adjustment being pulse width modulation and adjustment of the driving current of the LED emitter 4 . includes one of

In one embodiment, the transformed radiation R2, R21, R22 propagates in the primary transformation direction D2 towards the user interface surface 2a without application of radiation filtering.

The pixel structure 1 may comprise at least three LED emitters 4 , wherein at least one first wavelength conversion unit 5 is operably connected to the first LED emitter 4 and wherein at least one first wavelength conversion unit 5 is operably connected to the first LED emitter 4 . The second wavelength conversion unit 5 is operably connected to the second LED emitter 4 . As shown in FIG. 2B , the pixel structure 1 may include six LED emitters 4 , wherein a first pair of LED emitters is operably connected to a first wavelength conversion unit 5 , Two pairs of LED emitters 4 are operatively connected to the second wavelength conversion unit 5 . The first wavelength conversion unit 5 is preferably configured to convert the emitted radiation R1 from the first pair of LED emitters 4 into first converted radiation R2, and the second wavelength conversion unit 5 ) is preferably configured to convert the emitted radiation R1 from the second pair of LED emitters 4 into a second converted radiation R2.

As also shown in FIG. 2 b , each LED emitter 4 of the third pair of LED emitters 4 may be operably connected to either a radiation scattering unit 6 or a further wavelength conversion unit 5 . can When the emitted radiation R1 is in the range of the ultraviolet spectrum, the third pair of LED emitters 4 are preferably each operably connected to one further wavelength conversion unit 5, wherein the further wavelength conversion unit 5 is configured to convert the emitted radiation R1 in the ultraviolet spectrum from the third pair of LED emitters 4 into a third converted radiation R3 eg in the blue spectral range (not shown). Instead, when the emitted radiation R1 is in the blue spectral range, the third pair of LED emitters 4 are preferably each operatively connected to one radiation scattering unit 5 . Each LED emitter 4 can be operably connected to one wavelength conversion unit 5, optionally the connection is a contact layer for each LED emitter, such as for example a metal contact layer shown as a bottom layer in FIG. 3B. an anode, and the substrate 3 includes a cathode layer. The metal contact layer supplies current to the LED emitter and prevents unwanted emitted radiation R1 towards the bottom of the LED emitter and thus the substrate 3 .

10 shows an electronic device 13 comprising an electronic display 2 with a user interface surface 2a and at least one pixel structure 1 . Pixel structure 1 allows emission radiation R1 of one emission wavelength to be emitted in multiple emission directions D2,...Dn in main emission plane P1 as shown in Fig. 2B, so that emission radiation converting at least a portion of (R1) into converted radiation (R2, R21, R22) of at least one converted wavelength, and a main conversion direction (D1) perpendicular to the main emission plane (P1) and the user interface surface (2a) It is configured to direct the radiation (R2, R21, R22) converted to . The main emission plane P1 extends substantially parallel to the user interface surface 2a. The pixel structure 1 is configured to convert the emission radiation into at least one, preferably several converted wavelengths, the different converted wavelengths being different from each other and different from the emission wavelength.

As shown in Figs. 11 to 18, the electronic device 13 may include a plurality of identical pixel structures 1, the pixel structures 1 being distributed in a two-dimensional pattern on the main emitting surface P1. . The two-dimensional pattern includes rows of pixel structures 1 and columns of pixel structures 1, and the rows extend in parallel and intersect the columns at a vertical angle. The number of pixel structures 1 in an individual row is independent of the number of pixel structures 1 in adjacent rows, for which FIG. 17 shows alternately one and two pixel structures 1 in each row and 18 shows alternately two and three pixel structures 1 in each row. Correspondingly, the number of pixel structures 1 in an individual column is independent of the number of pixel structures 1 in adjacent columns, for which Figure 17 alternates two and three pixel structures 1 in each column. , and Fig. 18 shows alternately one and two pixel structures 1 in each column. This distribution of pixel structures 1 may allow maximization of the number of pixel structures 1 in an area comprising a two-dimensional pattern.

As shown in FIG. 13 , the plurality of pixel structures 1 can be distributed in a first pitch according to a two-dimensional pattern, wherein at least a first emission direction D2 of the emission radiation R1 of the individual pixel structures 1 aligned with the corresponding first emission direction D2 of the adjacent pixel structure 1 . 13, the second, third and fourth emission directions D3, D4 and D5 correspond to the corresponding second, third and fourth emission directions D3 and D4 of the adjacent pixel structure 1. and D5) can also be aligned. That is, the pixel structures 1 can be arranged in a two-dimensional rectangular grid pattern, the number of pixel structures 1 in a row, the number of pixel structures 1 in a column, the distance between rows, and the distance between columns constant The pitch is the distance between the center points of adjacent pixel structures 1 . This type of aligned arrangement is suitable when the absorption path (A) length is small compared to the pitch.

11, 12 and 14 to 18, the plurality of pixel structures 1 may instead be distributed in a second pitch according to a two-dimensional pattern, with the emission radiation R1 of the individual pixel structures 1 being At least the first emission direction D2 is misaligned with the corresponding first emission direction D2 of the adjacent pixel structure 1 . Preferably, the misaligned emission directions extend parallel, such that all pixel structures 1 are misaligned in the same direction by the same amount, for example by being rotated in the main emission plane P1 with respect to the column and row patterns.

Regardless of possible rotation, the pixel structure 1 can be arranged such that its center points are aligned in both directions of the two-dimensional pattern as shown in Figs. 11, 12 and 15. As shown in Figs. 14 and 16, the pixel structure 1 may be arranged such that its center point is aligned in one direction of the two-dimensional pattern and offset in the other direction. As shown in Figs. 17 and 18, the pixel structure 1 may be arranged such that its center point is misaligned in both directions of the two-dimensional pattern. The rotated misalignment arrangement is suitable when the absorption path (A) length is large compared to the pitch.

The misalignment allows an extension of the length of the absorption path A of each such pixel structure 1 having one or several misaligned emission directions. Because the emission directions are misaligned and do not extend along the same row or column, but instead within the empty area between those rows and columns, the length of each absorption path A is less than that of the adjacent absorption path A. limited Thus, the dimension of the absorption path A may exceed, for example, the external dimension of the wavelength conversion unit 5 in the main emission plane P1, i.e. the length of the absorption path A is the wavelength conversion that it extends. It may be longer than the length of the unit 5, or longer than the width of the wavelength conversion unit 5. For example, FIG. 11 shows an embodiment in which the absorption path A is folded twice at both ends of the wavelength conversion unit 5, and FIG. 12 shows an embodiment in which the absorption path A is bent.

14 to 18 show embodiments in which the pitch between adjacent pixel structures 1 is reduced. In Fig. 15, the pitch is similar to the length of the absorption path A so that two adjacent absorption paths cannot fit on a straight line between pixels. Accordingly, the emission direction of each pixel structure 1 is such that the absorption path A of one pixel structure 1 is adjacent to the absorption path A of the adjacent pixel structure 1 without overlapping the pixel structure 1. ) is rotated for the pattern of Thus, the pitch between the pixel structures 1 is maximally utilized for the absorption path A. The absorption path (A) must be sufficiently long to ensure a high color conversion efficiency and high absorption of the emitted radiation (R1), especially in the blue spectral range.

14 shows that the first emitting direction D2 and the second emitting direction D3 of an individual pixel structure 1 are side by side with respect to the corresponding first emitting direction D2 and second emitting direction D3 of adjacent pixel structures. It shows an embodiment in which the third and fourth emission directions D4 and D5 are aligned because the absorption path lengths required for emission from D4 and D5 are shorter, while misaligned to indicate an offset.

15 and 16 show that all of the first emission direction D2, the second emission direction D3, the third emission direction D4 and the fourth emission direction D5 of an individual pixel structure 1 are adjacent pixel structures. Embodiments are shown in which the two-dimensional pattern comprises one or several interconnected parallelograms misaligned with the corresponding emission directions (D2, D3, D4, D5).

17 and 18 show that all of the first emission direction D2, the second emission direction D3, the third emission direction D4 and the fourth emission direction D5 of an individual pixel structure 1 are adjacent pixel structures. misaligned to exhibit lateral offsets with the corresponding emission directions (D2, D3, D4, D5), so that the two-dimensional pattern comprises a honeycomb pattern of the distributed pixel structure (1).

As described above, the pixel structure 1 can be separated by arrangement, i.e., the first pitch, with a first pitch. In this case, the pixel structure 1 is such that the absorption path(s) A of the wavelength conversion unit(s) 5 of an individual pixel structure 1 are aligned with the corresponding absorption path A of an adjacent pixel structure. , aligned in at least one of a column direction and a row direction.

As described above, the pixel structure 1 may be arranged in a two-dimensional array. Each pixel structure 1 may occupy the same sized area and/or may have the same length of absorption path(s) A as the other pixel structure 1 . The absorption length may be 10-500 μm, preferably <20 μm. The pitch of the pixel structure 1 in the two-dimensional array is 20-150 μm in display applications configured such that the distance between the user's eye and the user interface surface 2a is less than 1 m, i.e., in a near view display such as a smartphone. , preferably 30-80 μm. Correspondingly, the second pitch is ≥70 μm, preferably ≥100 μm, in display applications configured such that the corresponding distance between the user's eye and the user interface surface 2a is ≥0.5 m, ie in a far view display such as a TV. can be

A plurality of pixel structures 1 distributed in a second pitch can be rotated by an angle β in the main emission plane P1, as shown in FIGS. 11, 12, 15, 16 and 18, so that the individual pixel structures The absorption path A of the wavelength conversion unit 5 in (1) is misaligned with the corresponding absorption path A of the adjacent pixel structure.

Further, the pixel structures 1 of individual rows may be offset in the column direction with respect to the pixel structures 1 of adjacent rows, as shown in FIGS. 14, 16 and 17 . Correspondingly, the pixel structures 1 of individual columns may be offset in the row direction with respect to the pixel structures 1 of adjacent columns, as shown in FIG. 18 .

Various aspects and implementations have been described herein in connection with various embodiments. However, other variations to the disclosed embodiments may be understood and practiced by those skilled in the art in practicing the claimed subject matter from a study of the drawings, disclosure and appended claims. The word "comprising" in the claims does not exclude other elements or steps, and singular expressions do not exclude the plural. A single processor or other unit may perform the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage. The computer program may be stored/distributed on any suitable medium, for example an optical storage medium or a solid state medium supplied with or as part of other hardware, but may be distributed in other forms via the Internet or other wired or wireless communication system. can

Reference signs used in the claims should not be construed as limiting the scope. Unless otherwise indicated, the drawings are intended to be read along with the specification (eg, cross hatching, arrangement of parts, proportions, extents, etc.) and are to be considered part of the entire written description of the present disclosure. The terms "horizontal," "vertical," "left," "right," "above," and "below," as well as their adjective and adverbial derivatives (e.g., "horizontally," "to the right," " "Upward" etc.) simply indicates the orientation of the illustrated structure when the particular figure is facing the reader. Similarly, the terms "inwardly" and "outwardly" generally refer to the orientation of a surface relative to an axis of extension or axis of rotation, as appropriate.

Claims (26)

A pixel structure (1) for an electronic display (2), comprising:
The pixel structure 1 is
- a substrate (3);
- at least one LED emitter 4 arranged on said substrate 3 - said LED emitter 4 configured to emit emission radiation R1, said emission radiation R1 having an emission wavelength within the range and emitted in one or more emission directions (D2, ..., Dn) within the main emission plane (P1); and
- at least one wavelength conversion unit (5) arranged adjacent to the LED emitter (4) on the substrate (3) - said wavelength conversion unit (5) converting the emitted radiation (R1) into converted radiation (R2). configured to convert, wherein the converted radiation (R2) is within the converted wavelength range and propagates from the wavelength conversion unit (5) in a main conversion direction (D1) perpendicular to the main emission plane (P1); ,
the converted wavelength range is different from the emission wavelength range;
Pixel structure (1). According to claim 1,
the emission wavelength range is either a blue spectral range or an ultraviolet spectral range;
If the pixel structure (1) comprises at least two LED emitters (4), the LED emitters (4) are configured to emit radiation having the same wavelength,
Pixel structure (1). According to claim 1 or 2,
comprising at least two wavelength conversion units (5), each wavelength conversion unit (5) converting the emitted radiation (R1) within the emission wavelength range to the converted radiation (R2) within one of a plurality of different converted wavelength ranges; ) configured to convert to
Pixel structure (1). According to claim 3,
at least one first wavelength conversion unit (5) is configured to convert the emitted radiation (R1) into a first converted radiation (R21) within a first converted wavelength range;
The at least one second wavelength conversion unit (5) is configured to convert the emission radiation (R1) into a second converted radiation (R22) within a second converted wavelength range, the second converted wavelength range being the first converted wavelength range. 1 at least partially different from the converted wavelength range,
Pixel structure (1). According to claim 4,
wherein the first converted wavelength range is within the red spectral range and the second converted wavelength range is within the green spectral range;
Pixel structure (1). According to any one of claims 1 to 5,
The LED emitter 4 is configured to emit only emission radiation R1 in the main emission plane P1, or
The emission radiation R1 or at least a part of the emission radiation R1 emitted in the main emission plane P1 by the LED emitter 4 is converted in the wavelength conversion unit 5 into radiation R2. converted,
Pixel structure (1). According to any one of claims 1 to 5,
If the pixel structure (1) comprises at least two LED emitters (4), at least one of the LED emitters (4) is configured to emit emission radiation (R1) in the main conversion direction (D1),
display device. According to any one of claims 1 to 7,
and at least one radiation scattering unit (6) arranged adjacent to the LED emitter (4) on the substrate (3), wherein the scattering unit (6) emits radiation propagating in the main emission plane (P1). configured to redirect (R1) in the main transform direction (D1),
Pixel structure (1). According to any one of claims 1 to 8,
the wavelength conversion unit 5 comprises a wavelength conversion material, the wavelength conversion material preferably comprises a matrix material and wavelength conversion particles distributed in the matrix material;
Pixel structure (1). According to claim 9,
The wavelength conversion particle is a quantum dot or phosphorus material,
Pixel structure (1). According to any one of claims 1 to 10,
the wavelength conversion unit (5) includes at least one barrier (7) extending along the periphery of the wavelength conversion unit (5) in the main conversion direction (D1);
The barrier 7 is configured to extend an absorption path A of the wavelength conversion unit 5, the absorption path A extends in the main emission plane P1, and the emission radiation R1 is propagate along the absorption path (A),
said conversion of the emitted radiation (R1) to converted radiation (R2) occurs simultaneously with the propagation;
Pixel structure (1). According to claim 11,
at least one wall reflector (8) arranged on the surface of the barrier (7) extending at least partially in the main transforming direction (D1);
The wall reflector 8 is such that the absorption path A of the wavelength conversion unit 5 extends within the main emission plane P1, so that the emission radiation R1 propagating along the absorption path A ) configured to redirect the
Pixel structure (1). According to any one of claims 1 to 12,
further comprising at least one bottom reflector (9) arranged between the wavelength conversion unit (5) and the substrate (3);
The bottom reflector 9 extends at least partially parallel to the main emission plane P1 and redirects the converted radiation R2 propagating in the wavelength conversion unit 4 to the main conversion direction D1. composed of
Pixel structure (1). According to claim 13,
wherein the wavelength conversion unit (5) comprises a waveguide structure (10) configured to guide the emission radiation (R1) when the emission radiation (R1) propagates within the wavelength conversion unit (5).
Pixel structure (1). According to any one of claims 1 to 14,
The wavelength conversion unit 5 is configured such that at least one wavelength conversion unit surface 5a, 5b extends at an angle α to the main substrate plane P2 of the substrate 3, the surface 5a is directed away from the substrate 3 and the surface 5b extends adjacent to the substrate 3,
Pixel structure (1). According to claim 15,
One of the wavelength conversion unit (5) and the substrate (3) is tapered as it extends along the main emission plane (P1) or the main substrate plane (P2),
Pixel structure (1). According to any one of claims 1 to 16,
and at least one optical functional element (11) arranged on the wavelength conversion unit surface (5a) facing away from the substrate (3), the optical functional element (11) of the wavelength conversion unit surface (5a). Arranged on top or integrated with the wavelength conversion unit surface (5a),
Pixel structure (1). According to claim 17,
The optical functional element 11 is at least one of a refractive lens and a diffractive lens,
Pixel structure (1). According to claim 17,
The optical functional element 11 is one of a surface structure, preferably a surface lattice structure, a surface roughness structure, a surface coating structure or a micro-pillar,
Pixel structure (1). According to any one of claims 1 to 19,
Several of the LED emitters 4 are operably connected to one wavelength conversion unit 5, and the LED emitters 4 simultaneously and independently emit emission radiation R1 to the wavelength conversion unit 5. configured to
Pixel structure (1). The method of any one of claims 1 to 20,
and a control device (12) for adjusting the total output of the converted radiation (R2, R21, R22), said adjustment being pulse-width-modulating and adjusting the drive current of the LED emitter(s) (4). including one of
Pixel structure (1). Electronic device (13) comprising an electronic display (2) with a user interface surface (2a) and at least one pixel structure (1) according to any one of claims 1 to 21,
The pixel structure 1,
allow emission radiation (R1) of one emission wavelength to be emitted in multiple emission directions (D2,...,Dn) within a main emission plane (P1) - the main emission plane (P1) is the user interface surface ( 2a) extended parallel to -,
converting at least a portion of the emission radiation (R1) into converted radiation (R2, R21, R22) of at least one converted wavelength, wherein the converted wavelength is different from the emission wavelength;
configured to direct the converted radiation (R2, R21, R22) in a main transformation direction (D1) perpendicular to the main emission plane (P1) and the user interface surface (2a);
Electronic device (13). The method of claim 22,
comprising a plurality of identical pixel structures (1), said pixel structures (1) being distributed in said main emission plane (P1) along a two-dimensional pattern;
the two-dimensional pattern includes rows of pixel structures (1) and columns of pixel structures (1), the rows extending in parallel and intersecting the columns at a vertical angle;
The number of pixel structures 1 in an individual row is independent of the number of pixel structures 1 in adjacent rows;
the number of pixel structures 1 in an individual column is independent of the number of pixel structures 1 in adjacent columns;
The distribution of pixel structures (1) allows maximization of the number of pixel structures (1) in an area containing the two-dimensional pattern.
Electronic device (13). According to claim 23,
The plurality of pixel structures 1 is such that at least a first emission direction D2 of the emission radiation R1 of an individual pixel structure 1 is different from a corresponding first emission direction D2 of an adjacent pixel structure 1 . Distributed at a first pitch along the two-dimensional pattern to be aligned,
Electronic device (13). According to claim 23,
The plurality of pixel structures 1 is such that at least a first emission direction D2 of the emission radiation R1 of an individual pixel structure 1 is different from a corresponding first emission direction D2 of an adjacent pixel structure 1 . Distributed at a second pitch along the two-dimensional pattern so as to be misaligned, the misalignment being lateral offset and/or angular offset with respect to the orientation of each pixel structure (1).
Electronic device (13). According to claims 24 and 25,
When the length of the absorption path (A) is fixed, the length is 10-500 μm, preferably <20 μm,
the second pitch is 20-150 μm, preferably 30-80 μm, in display applications configured such that the distance between a user's eye and the user interface surface (2a) is <1 m;
the second pitch is ≥70 μm, preferably ≥100 μm, in display applications configured such that the corresponding distance between the user's eye and the user interface surface (2a) is ≥0.5 m;
Electronic device (13).

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